A variety of apparatuses may be used for actuating objects or holding together objects that need to be later released. For example, an explosive bolt can be used to attach two or more objects and may later release the objects with an explosive force. An explosive bolt incorporates explosives that cause an explosion when initiated or triggered. The explosion breaks apart the explosive bolt to release the objects. The problem with explosive bolts is that they are dangerous to handle because of the explosives and the explosion may exert a large amount of shock load that may damage fragile machinery. In addition, shrapnel pieces or foreign object debris (FOD) resulting from the explosion can interfere with machinery or optics.
A variety of systems include electrically operated components configured to operate at a specified current or within a range of currents. Exposure of these systems to elevated currents may damage the components and require repair or replacement. Fuses are electrically coupled with these components and are triggered by elevated currents that melt the fuse material and open a circuit. Opening of the circuit interrupts the flow of electricity to the component, shutting it down, and preventing damage to the component.
Electrically operated components and the fuses associated with them are subject to current spikes over the life of the fuse. Fluctuations in current raise the temperature of the fuse material even where the fluctuation is not sufficient to melt the fuse. Over time current fluctuations (e.g., from poor power conditioning) cause the fuse material to sublimate and thereby the fuse material is gradually decreased. The fuse material, along with its width and thickness are specified at construction to ensure melting of the fuse material at a current overload threshold. The gradual sublimation of the fuse material correspondingly lowers the threshold for melting of the fuse and allows the fuse to melt at lower currents. In some cases the partially sublimated fuse melts during a fluctuation in current that is below the desired current overload threshold. The electrically operated component coupled with such a fuse may have its operation interrupted unnecessarily through melting of the fuse in error. Alternatively, fuses with thicker fuse materials may be used, but thicker fuse materials increase the current overload needed to melt the fuse and thereby risk exposing the electrically operated components to currents spikes without operation of the fuse.
Furthermore, fuses are used with sensitive electronic components in some instances (e.g., optical systems, radio systems, radar systems and the like). The fuse material at least partially vaporizes within the fuse body when subjected to a current overload. The vaporized metal of the fuse allows for continued arcing of electricity between the fuse contacts. The arcing of electricity creates undesirable radio frequency signals that negatively affect these sensitive components decreasing or interrupting their operation.